From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1EA37306B3B; Sat, 12 Sep 2026 13:53:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789221183; cv=none; b=aGenqcMs5K/Jg+ZanAPLKxK3Tu5UxnzY2OPsHSlK7MGN76Y0jxFBRLGL38mWsZFt/sp8E35EAjb7rQbl6XF3//JLJfa7WPZ0daP/VahvvkxuLEReBLMhaGwB4eIMYZnfvfPf2gQvnIGTdNky+zCGNtLH7Hsu3laA/XKmfz0KoVY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789221183; c=relaxed/simple; bh=Bk69ws+dbX73ExRvs2HPqByctHj6BgtYDzry14mJ8aw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pV9CQTAjDvcc15WqCSr+LyGO8VpWpdOoIQQOezUNo9wQBxDUXt/oPW3urOJX8jRhVSRX+ssVrLpJznTj+tfCx7qjzeA0GjHwlLZSQyhTj/oNa8E8VVgAVo/qwK3N/pftzrD2kM+++0QdX8aFneXi125Pos/Ej6VAZ32TBKWTDZQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0m/jo0tl; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="0m/jo0tl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07CF41F000FF; Sat, 12 Sep 2026 13:53:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789221182; bh=0lRyf3dPvjp9hfO3C8J3ioXs8wdKiGj7hYXUWE2R5qI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=0m/jo0tlssKSLJvcoAWaPQktrxlyi+01Ac1YQt6TmiY2JrG8eJA6IwVBU4LEnJdq/ fh+nDpXHBbYac0rTyEZ3Ue1/BNRqUbECMZ8W61MN6gmPoKS+22zU2Swzg9culno310 DoRu6ZeKc5GuRKFRV5NuY00v1Yb0oADbWmYpUuCM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , syzbot+bbb6dad313f4aaa8da6b@syzkaller.appspotmail.com, Aleksandr Nogikh , Takashi Iwai Subject: [PATCH 6.6 0330/1424] usb: gadget: midi2: Fix null-pointer dereference in f_midi2_free_ep_reqs Date: Sat, 12 Sep 2026 08:46:02 +0200 Message-ID: <20260912065614.678160077@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.279695368@linuxfoundation.org> References: <20260912065607.279695368@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Aleksandr Nogikh commit f0efaf1872949e96d213c8e910fd9517f7d7c406 upstream. A null-pointer dereference occurs in f_midi2_free_ep_reqs() when attempting to clean up an endpoint that was never initialized. When configuring the MIDI 2.0 gadget via configfs and setting the block direction to SNDRV_UMP_DIR_INPUT, the initialization of the midi1_ep_out endpoint is explicitly skipped during the gadget bind phase (f_midi2_bind()). As a result, the usb_ep->card field remains NULL. Later, when the host sets the alternate setting, f_midi2_set_alt() unconditionally stops both the IN and OUT endpoints by calling f_midi2_stop_eps(), which in turn calls f_midi2_free_ep_reqs() for both endpoints. When f_midi2_free_ep_reqs() is called for the uninitialized midi1_ep_out, it attempts to dereference usb_ep->card to determine the number of requests to free, leading to a crash. Fix this by using usb_ep->num_reqs instead of usb_ep->card->info.num_reqs in f_midi2_free_ep_reqs(). usb_ep->num_reqs is correctly set during f_midi2_init_ep() and remains 0 if the endpoint was never initialized, safely avoiding the loop. For consistency, apply the same change to f_midi2_alloc_ep_reqs(). Oops: general protection fault, probably for non-canonical address 0xdffffc00000000ee: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000770-0x0000000000000777] ... RIP: 0010:f_midi2_free_ep_reqs drivers/usb/gadget/function/f_midi2.c:1166 [inline] RIP: 0010:f_midi2_stop_eps+0x28e/0x4d0 drivers/usb/gadget/function/f_midi2.c:1246 ... Call Trace: f_midi2_set_alt+0x11c/0xf00 drivers/usb/gadget/function/f_midi2.c:1296 composite_setup+0x1ffd/0x3480 drivers/usb/gadget/composite.c:1933 configfs_composite_setup+0xbd/0x100 drivers/usb/gadget/configfs.c:1877 Fixes: 8b645922b223 ("usb: gadget: Add support for USB MIDI 2.0 function driver") Cc: stable Assisted-by: Gemini:gemini-3.5-flash Gemini:gemini-3.1-pro-preview syzbot Reported-by: syzbot+bbb6dad313f4aaa8da6b@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=bbb6dad313f4aaa8da6b Link: https://syzkaller.appspot.com/ai_job?id=8ce30b1a-8cf7-4e38-bcf7-1f69e6f6313f Signed-off-by: Aleksandr Nogikh Reviewed-by: Takashi Iwai Closes: https://syzkaller.appspot.com/bug?extid=01a17afb30637396955e Link: https://patch.msgid.link/cafe65f4-e1bb-46a3-901d-732814b861b2@mail.kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_midi2.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/usb/gadget/function/f_midi2.c b/drivers/usb/gadget/function/f_midi2.c index a4b72a6fad8a..e0b743dfaba5 100644 --- a/drivers/usb/gadget/function/f_midi2.c +++ b/drivers/usb/gadget/function/f_midi2.c @@ -1145,7 +1145,7 @@ static int f_midi2_alloc_ep_reqs(struct f_midi2_usb_ep *usb_ep) if (!usb_ep->reqs) return -EINVAL; - for (i = 0; i < midi2->info.num_reqs; i++) { + for (i = 0; i < usb_ep->num_reqs; i++) { if (usb_ep->reqs[i].req) continue; usb_ep->reqs[i].req = alloc_ep_req(usb_ep->usb_ep, @@ -1160,10 +1160,9 @@ static int f_midi2_alloc_ep_reqs(struct f_midi2_usb_ep *usb_ep) /* Free allocated requests */ static void f_midi2_free_ep_reqs(struct f_midi2_usb_ep *usb_ep) { - struct f_midi2 *midi2 = usb_ep->card; int i; - for (i = 0; i < midi2->info.num_reqs; i++) { + for (i = 0; i < usb_ep->num_reqs; i++) { if (!usb_ep->reqs[i].req) continue; free_ep_req(usb_ep->usb_ep, usb_ep->reqs[i].req); -- 2.55.0